Surgery – Instruments – Electrical application
Reexamination Certificate
2000-12-18
2003-07-15
Cohen, Lee (Department: 3739)
Surgery
Instruments
Electrical application
C606S033000, C607S101000
Reexamination Certificate
active
06592579
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to apparatus, methods, and computer simulations highly suitable for treatment of benign prostatic hyperplasia (BPH) and, more particularly, to a unique catheter for microwave treatment of BPH to necrose prostatic tissue while protecting urethral tissue and computer simulations relating to the same.
2. Description of Prior Art
Benign prostatic hypertrophy or hyperplasia (BPH) is one of the most common medical problems experienced by men over 50 years old. Urinary tract obstruction due to prostatic hyperplasia has been recognized since the earliest days of medicine. Hyperplastic enlargement of the prostate gland, or enlargement due to abnormal but benign multiplication of the cells thereof, often leads to compression of the urethra thereby resulting in obstruction of the urinary tract. Common symptoms that develop from this condition may include more frequent urination, decrease in urinary flow, nocturia, pain, and discomfort. The incidence of BPH in men over 50 years of age is approximately 50 percent and increases to over 75 percent in men over 80 years of age. Symptoms of urinary obstruction occur most frequently between the ages of 65 and 70 when approximately 65 percent of men in the age group have prostatic enlargement.
When treatment by drug therapy is not sufficiently effective, surgical procedures for treating BPH are available but have potential side effects. General surgical risks apply such as anesthesia related morbidity, hemorrhage, coagulopathies, pulmonary emboli, electrolyte imbalance, and the like. Other problems that may occur from surgical correction include cardiac complications, bladder perforation, incontinence, infection, urethral or bladder neck stricture, retention of prostatic chips, and infertility. Due to the problems of surgery, many or even most patients delay treatment. However, the delay of treatment may lead to other complications including obstructive lesion in the prostate, chronic infection, and the like. Therefore it is unquestionable that a need exists for improved surgical or non-surgical methods for treating BPH.
Microwaves and other techniques have been used to necrose malignant, benign, and other types of cells and tissues including glandular and stromal nodules characteristic of benign prostate hyperplasia. However, problems encountered include a lack of focusing or direction of the energy thereby resulting in damage of healthy tissue.
The following patents disclose attempts to solve the above discussed difficult problems and related problems.
U.S. Pat. Nos. 5,904,709, issued May 18, 1999, to Arndt et al., and incorporated herein, discloses a method and apparatus for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue to treat ventricular tachycardia and other arrhythmias while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In operation, microwave energy between about 1 Gigahertz and 12 Gigahertz is applied to the monopole microwave radiator having a surface wave limiter. A test setup provides physical testing of microwave radiators to determine the temperature profile created in actual heart tissue or ersatz heart tissue. Saline solution pumped over the heart tissue with a peristaltic pump simulates blood flow. Optical temperature sensors disposed at various tissue depths within the heart tissue detect the temperature profile without creating any electromagnetic interference. The method may be used to produce a desired temperature profile in other body tissues reachable by catheter such as tumors and the like.
U.S. Pat. No. 5,843,144, issued Dec. 1, 1998, to Rudie et al., discloses a method for treating an individual with diseased prostatic tissue, such as benign prostatic hyperplasia, including inserting a catheter into a urethra to position a microwave antenna located within the catheter adjacent a prostatic region of the urethra. A microwave antenna is then driven within a power range for applying microwave energy substantially continuously to prostatic tissue to heat the prostatic tissue surrounding the microwave antenna at a temperature and for a time period sufficient to cause necrosis of the prostatic tissue.
U.S. Pat. No. 5,843,026, issued Dec. 1, 1998, to Edwards et al., discloses a method and apparatus for delivering controlled heat to perform ablation to treat the benign prosthetic hypertrophy or hyperplasia (BPH). According to the method and the apparatus, the energy is transferred directly into the tissue mass which is to be treated in such a manner as to provide tissue ablation without damage to surrounding tissues. Automatic shut-off occurs when any one of a number of surrounding areas to include the urethra or surrounding mass or the adjacent organs exceed predetermined safe temperature limits. The constant application of the radio frequency energy over a maintained determined time provides a safe procedure which avoids electrosurgical and other invasive operations while providing fast relief to BPH with a short recovery time. The procedure may be accomplished in a doctor's office without the need for hospitalization or surgery.
U.S. Pat. No. 5,830,179, issued Nov. 3, 1998, to Mikus et al., discloses a stent system and method for use in the prostate gland. The stent is made of a shape memory alloy such as nitinol, and has a low temperature martensite state, with a martensite transition temperature below body temperature, and a high temperature austenite state, with an austenite transition temperature at or above body temperature, and a memorized shape in the high temperature austenite state which is a helical coil of diameter large enough to hold the prostatic urethra open. The stent is used to heat the prostate and is left in the prostatic urethra while the prostate heals. After the prostate is substantially healed, the stent is cooled to its martensite state and is easily removed from the urethra.
U.S. Pat. No. 5,800,486, issued Sep. 1, 1998, to Thome et al., discloses an intraurethral catheter which includes a microwave antenna and a cooling lumen structure substantially surrounding the antenna. A cooling balloon partially surrounds the cooling lumens on one side of the catheter adjacent the microwave antenna. The cooling balloon improves wall contact between the catheter and a wall of the urethra to improve cooling of the urethra. The cooling balloon communicates with the cooling lumen structure to permit circulation of cooling fluid through the cooling balloon.
U.S. Pat. No. 5,800,378, issued Sep. 1, 1998, to Edwards et al., discloses a medical probe device comprising a catheter having a stylet guide housing with one or more stylet ports in a side wall thereof and a stylet guide for directing a flexible stylet outward through the stylet port and through intervening tissue at a preselected, adjustable angle to a target tissue. The total catheter assembly includes a stylet guide lumen communicating with the stylet port and a stylet positioned in said stylet guide lumen for longitudinal movement from the port through intervening tissue to target tissue. The stylet can be an electrical conductor enclosed within a non-conductive layer, the electrical conductor being a radio frequency electrode. Preferably, the non-conductive layer is a sleeve which is axially moveable on the electrical conductor to expose a selected portion of the electrical conductor surface in the target tissue. The stylet can also be a microwave antenna. The catheter can include one or more inflatable balloons located adjacent to the stylet port for anchoring the catheter or dilatio
Arndt G. Dickey
Carl James
Ngo Phong
Raffoul George W.
Cohen Lee
Johnson, III Henry M
Ro Theodore U.
The United States of America as represented by the Administrator
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